Abstract: Enzyme-assisted extraction of total flavonoids from Speranskia was studied in this paper.Frist enzymatic hydrolysis by cellulase,and then reflux by ethanol to extract total flavonoids.Ethanol concentration of 70% and solid/liquid ratio of 1:20 g / mL were fixed.The preferred extraction conditions were determined by single factor experiment and orthogonal experiment.The experiment reveals that:cellulase concentration of 2 U/mL,enzymatic hydrolysis pH of 4.5,enzymatic hydrolysis temperature of 45 ℃ and enzymatic hydrolysis time of 2.0 h.The extraction ratio of total flavonoids reached up to 1.27% by using spectrophotometry.Antioxidant effects of flavonoids、rutin solution and BHT were measured to remove hydroxyl radicals by comparative experiments.Antioxidant experiments showed that flavonoids from speranskia showed a strong scavenging effect on hydroxyl radicals.

Key words: enzyme-assisted extraction, speranskia, flavonoids, extraction ratio, scavenging effect, hydroxyl radicals